Exhaust conversion systems

ABSTRACT

I disclose a conversion system for an exhaust duct or the like through which partially reacted gases are circulated, said system comprising a venturi induction member mounted in the exhaust duct and having a circumferential array of radially extending apertures for inducting a reactant fluid into said duct upon passage of said gases therethrough said venturi member having inlet and outlet openings each having substantially the same cross-sectional area as that of the adjacent interior of said duct, said apertures being located in a thickened portion of said venturi member and having a length-to-diameter ratio capable of imposing a jetting action upon the reactant fluid passing therethrough so that thorough mixing of said reactant fluid and said gases is attained within said venturi member. Also disclosed are unique venturi configurations involving a throat ridge and induction apertures adjacent thereto for improved induction and mixing.

United States Paten Kaufmann, Jr.

3,657,878 1 1 Apr. 25, 1972 [54] EXHAUST CONVERSION SYSTEMS [72]Inventor: John Kaufmann, Jr., 3716 Woodrow Avenue, Pittsburgh, Pa. 15227[22] Filed: Apr. 14, 1970 [21] Appl. No.: 28,406

Related U.S. Application Data [62] Division of Ser. No. 767,602, Aug.30, 1968, Pat. No.

[52] U.S.Cl. ..60/319,23/277C,417/159 [51] '1nt.Cl ..F0ln 3/10 [58]Field of Search ..60/30; 23/2 C, 277 C, 288.3 F;

[56] References Cited UNITED STATES PATENTS 2,005,249 6/1935 Tietig..60/30 1071,11) 2/1937 Harger ....60/30 2,677,231 5/1954 Cornelius.......60/30 2,953,898 9/1960 Cornelius... ....60/30 3,032,969 5/1962Barnes ...60/30 Primary E.taminerDouglas Hart Attorney-Dan J. Smith [57]ABSTRACT I disclose a conversion system for an exhaust duct or the likethrough which partially reacted gases are circulated, said systemcomprising a venturi induction. member mounted in the exhaust duct andhaving a circumferential array of radially extending apertures forinducting a reactant fluid into said duct upon passage of said gasestherethrough said venturi member having inlet and outlet openings eachhaving substantially the same cross-sectional area as that of theadjacent interior of said duct, said apertures being located in athickened portion of said venturi member and having a length-to-diameterratio capable of imposing ajetting action upon the reactant fluidpassing therethrough so that thorough mixing of said reactant fluid andsaid gases is attained within said venturi member. Also disclosed areunique venturi configurations involving a throat ridge and inductionapertures adjacent thereto for improved induction and mixing.

PATENTEDAPR 25 I972 3, 657, 878

SHEET 1 BF 2 mvsmon Jo'lzzz Maze/712 /1'.

17 5 149 TOE/102% EXHAUST CONVERSION SYSTEMS This application is adivision'in-part of my copending application entitled EXHAUST CONVERSIONSYSTEMS, filed Aug. 30, 1968, Ser. No. 767,602, now U.S. Pat. No.3,543,510.

The present invention relates to novel venturi constructions and tomeans for reducing or eliminating altogether the noxious gases emittedfrom the exhaust systems of combustion operations, in particularinternal combustion engines, in order to reduce the air pollutionresulting from operation thereof. More particularly, the inventionrelates to means of the character described for completing thecombustion of internal combustion engine exhaust gases, irrespective ofengine speed, in order to convert them to innoccuous fluids.

Although my invention is described with primary reference to the exhaustsystem of internal combustion engines, it will become apparent as thisdescription proceeds that the invention is not limited to thisapplication. My exhaust conversion system is of general utility, and canbe installed in a variety of exhaust systems handling products ofincomplete combustion to oxidize potential air contaminants or insimilar systems handling high temperature oxidizable or combustiblegases. For example, it is contemplated that my conversion system orantipollution means can be installed in the exhausts of various types ofreaction motors, industrial furnaces and the like. The invention iscapable of analogous applications, as in the induction of various typesof reactant fluids other than combustion air. It is also contemplatedthat my novel venturi system can be used in conjunction with otherexhaust and/or inductional systems, such as vacuum or jet pumps.

It is well known that the various hydrocarbon fuels employed in thoseengines generally classed as internal combustion engines are notcompletely combusted therein. This unavoidable, incomplete combustion ofthe fuels thus employed results in the generation of substantialquantities of unburned or partially burned hydrocarbons, carbonmonoxide, and other noxious waste gases which are usually vented to theatmosphere through the exhaust system. It is also well known that thesenoxious gases constitute a health hazard owing to their pollutionaleffects in the atmosphere. In recent years the health hazard has grownto dangerous proportions as a result of the rapidly increasing numbersof automobiles and other vehicles powered by internal combustionengines.

Many proposals have been advanced previously for combatting this healthmenace, most of which have attempted to burn or oxidize the exhaustgases either by thermal or catalytic conversional techniques. In thecatalytic method, the exhaust gases leaving the engine are passedthrough a conversion unit in which the catalyst is suspended. Such unitsare rather bulky in construction and aretherefore difficult toaccommodate in most types of vehicles, where space is at a premium.Moreover, it is necessary to provide a carefully balanced supply ofoxygen or the like and to maintain a particular heat balance. Catalyticconverters therefore are difficult to maintain in proper adjustment evenunder ideal conditions and are virtually useless in the wide range ofdriving conditions encountered by the average vehicle.

in many of the thermal converting systems, an additional combustionchamber is required in the exhaust system of the engine. The combustionchamber is equally difficult to accommodate in the vehicle for the samereasons mentioned above in connection with the catalytic chamber. Manyof these exhaust combustion chambers are provided in the form ofafterburners which require additional fuel and an auxiliary ignitionsystem, in addition to auxiliary combustion air, to accomplish theconversion of the exhaust fumes. The use of secondary fuel, of course,decreases the efficiency of the vehicle considerably, and in the eventof failure of the ignition system or other malfunctioning in theafterburner, the noxious fumes from the engine exhaust are greatlyincreased by addition of the secondary fuel. Moreover, if either thecatalytic converter or the thermal converter are placed under the hoodof a conventionally constructed automobile, the danger to the vehiclesoccupants is considerably increased in the event of malfunctioning ofthese converters.

It has also been proposed to conduct auxiliary combustion air from ablower or from a source of compressed air directly into the inlet portsof the exhaust manifold of an internal combustion engine. Such anarrangement, as typified by the US. Pat. to Dworak No. 3,091,078, wouldutilize the exhaust manifold or manifolds as exhaust combustionchambers. However, as the incoming exhaust streams through each of theexhaust manifold inlet ports is pulsating, as dictated by the enginesoperating pattern, it is difficult, if not impossible, to maintain anysort of uniformity and continuity of combustion within the exhaustmanifold. Whatever combustion does occur in the exhaust manifold isinitiated at points very close to the exhaust valves of the engine withthe result that these valves are rapidly burned. The resultingturbulence of these gates which are thus combusted, within the manifoldmoreover interferes with the proper flow of exhaust gases therethrough.As a result, it has been found necessary to employ some sort ofcatalytic or thermal conversion unit downstream of the exhaust manifold.

In general, none of the prior proposals for combusting or convertingnoxious exhaust fumes into innoccuous substances have been successful.In those known systems wherein a substantial conversion has beeneffected, the physical size of the equipment required to make theconversion has precluded their use with internal combustion enginesemployed in most automobiles and other vehicles where space is at apremium.

In many of the previously proposed exhaust conversion systems, auxiliarycombustion air has been inducted into the exhaust stream by jetaspirators or by improperly shaped and improperly located venturiaspirators or the like. These devices provide an uncertain supply ofauxiliary combustion air at best, and under certain conditions forexample when the engine is idling or nearly so, the flow through the jetor venturi aspirator is reversed so that noxious exhaust fumes areemitted prematurely from the exhaust system, i.e. at a location wherethe fumes can enter the cab or passenger compartment of the vehicleresulting in a hazard to the occupants thereof. Examples of such priorproposals are the US. Pats. to Knopp No. 3,300,964 and Barnes No.3,032,969. In particular, the induction apertures of these proposals arenot located for optimum mixing or shaped for a jetting action to promotemixing of exhaust with the inducted combustion air or other reactant.

My researches in this field indicate that these devices would notfunction properly at all engine speeds owing to the shapes of theirventuri structures and the location of the air intake apertures. Asdescribed more fully below, to complete the combustion of the exhaustgases requires a careful addition and distribution of combustion airinto the exhaust duct. Under certain conditions, it is necessary tointroduce a particular type of glow ignition device to maintain ignitionof the exhaust gases.

Crank case scavenging arrangements utilizing the venturi principle areshown in Phillips US. Pat. No. 2,585,495 and Griswold US. Pat. No.1,766,900. The Phillips device would appear to add to atmosphericpollution, as apparently there is no attempt to oxidize the exhaust andcrank case gases.

Other exhaust handling systems are shown in the US. Pats. to CorneliusNo. 2,677,231 and No. 2,851,852 and in Bowen III et a1. U.S. Pat. No.2,772,147. In the Cornelius patents the several illustrated venturistructures provide minimal flow area and considerable obstruction to thepassage of the exhaust gases therethrough. Rather large and complicatedstructures are entailed for this reason. The Bowen venturi arrangementdoes not provide adequate induction and mixing of com bustion air tosolve the problems confronted by the present invention. The Bowenstructure further incorporates a catalytic conversion unit downstream ofthe mixing venturi.

I am also aware of a number of venturi pump and mixer structures asexemplified by the US. Pats. to Phillips No. 2,711,284 and Campbell No.2,493,387,. and French Pat. No. 233,502 to Mr. Laguilharre. Thesestructures likewise fail to provide the requisite induction and mixingaction, and attendant jetting action of my novel venturi structures.

I have solved these difiiculties of the prior art by providing a simpleyet reliable conversion or anti-pollution system for exhaust gases,which requires little or no additional space in the vehicle exhaustsystem or other exhaust system when my conversion means is mounted inthe exhaust duct forming part thereof. My conversion system includesmeans for inducting auxiliary combustion air directly into the vehicleexhaust system at a point where the heat of the exhaust system issufiicient to initiate and to drive the combustion of the exhaust fumessubstantially to completion. I have determined that the mostadvantageous point of entry for the auxiliary combustion air is adjacentthe outlet of the one or more exhaust manifolds of the vehicle engine.At this point the exhaust system is relatively steady, in contrast tothe pulsating stream at the exhaust manifold inlet ports. Furthermore,the usual cast iron construction of the exhaust manifold does not permita significant temperature drop in the hot exhaust gases between theexhaust ports of the individual cylinders and the exhaust manifoldoutlet. Accordingly, an adequate temperature level is available underall driving conditions of the vehicle to initiate and to sustain thecombustion of the exhaust gases in conjunction with the auxiliarycombustion air added by my conversion system. In certain applications,my conversion system also includes means for carefully metering theauxiliary combustion air supplied to the conversion system and forpreventing reverse flow from the conversion system for example when theengine is idling.

In order to afford proper induction and/or mixture of combustion air orother reactant with the exhaust gases, in particular at widely variableexhaust flow rates, I have found particular shapes of the venturistructure to be most effective. For example, depending upon theapplication of the invention, I provide the inner surfaces of theventuri structure with a certain curvature (inclusive, of course, ofrectilinear surfaces) in combination with particular angles and shapesof leading and trailing edges. The efficacy of my venturi structure isfurther enhanced by a particular location of the combustion air entranceapertures relative to the venturi throat and the use of a particularshape of surface surrounding or adjacent the apertures. For the samepurpose, I provide a particular shape of venturi throat structure.

In other applications of my invention, I have found that combustion ofthe exhaust gases is made even more complete by the use of two or moreventuri structures in series for superior mixing and/or inductionpurposes. With the use of multiple venturi structures, combustion aircan be supplied independently to one or more of the venturi structures.

Most applications of my conversion system, in addition to requiringlittle or no additional space for the exhaust system, involve no movingparts with a result that the possibilities of malfunctioning of thesystem are almost mil. In other forms of my conversion system, thosemoving parts which are utilized are simple and rugged in construction sothat maintenance of the system is minimized and its reliability isenhanced. Finally and most importantly, my novel conversion systemrequires little or no modification of existing exhaust ductwork so thatmy system can be installed on existing as well as newly manufacturedvehicle exhausts or on other exhaust systems.

I accomplish these desirable results by providing a conversion systemfor an exhaust duct or the like through which partially reacted gasesare circulated, said system comprising a venturi induction membermounted in the exhaust duct and having a circumferential array ofradially extending apertures for inducting a reactant fluid into saidduct upon passage of said gases therethrough, said venturi member havinginlet and outlet openings each having substantially the samecross-sectional area as that of the adjacent interior of said duct, saidapertures being located in a thickened portion of said venturi memberand having a length-to-diameter ratio capable of imposing a jettingaction upon the reactant fluid passing therethrough so that thoroughmixing of said reactant fluid and said gases is attained within saidventuri member.

I also desirably provide a similar conversion system wherein a checkvalve is coupled to said inlet port and is directed to prevent anoutflow of said gases therethrough when the velocity of said gasesthrough said duct is insufficient to generate a venturi effect.

I also desirably provide a similar conversion system wherein said lengthto diameter ratio varies between about 3:1 and about 5:1.

I also desirably provide a similar conversion system wherein saidexhaust duct is coupled to an internal combustion engine, said venturimember being coupled between an outlet port of an engine exhaustmanifold and an exhaust outlet pipe, said manifold and said pipe formingsaid exhaust duct sections.

I also desirably provide a similar conversion system wherein conduitmeans including a throttling valve are coupled to said venturiapertures, and means are provided for moving said valve toward openedand closed positions thereof in accordance with engine acceleration anddeceleration respectively, said moving means including fluid motivemeans coupled to said throttling valve and to an intake manifold of saidengine for energization thereby.

I also desirably provide a conversion system for an exhaust duct or thelike through which partially reacted gases are circulated, said systemcomprising a venturi induction member mounted in the exhaust duct andhaving a circumferential array of radially extending apertures forinducting reactant fluid into said duct upon passage of said gasestherethrough, said venturi member having a throat area defined by aninwardly extending peripheral ridge, said array of apertures beingdisposed adjacent said ridge. I also desirably provide a similarconversion system wherein said aperture array is positioned downstreamof said ridge, and the inward opening of each of said apertures issubstantially contingent with said ridge.

I also desirably provide a similar conversion system wherein the inwardsurfaces of said venturi member on either side of said ridge are definedby substantially frustoconical sections respectively.

During the foregoing discussion various objects, features and advantagesof the invention have been alluded to. These and other objects, featuresand advantages of the invention together with structural details thereofwill be elaborated upon during the forthcoming description of certainpresently preferred embodiments of the invention together with presentlypreferred methods of practicing the same.

In the accompanying drawings I have shown certain presentlypreferredembodiments of the invention and have illustrated certainpresently preferred methods of practicing the same in which:

FIG. 1 is an elevational view, partly in section of one form of exhaustsystem, including for example an internal combustion engine and itsexhaust, for which my novel exhaust conversion or anti-pollutionalsystem is suitable;

FIG. 2 is a partial longitudinally sectioned view of a modified form ofmy conversion system;

FIG. 3 is a longitudinally sectioned view of still another form of myconversion system;

FIG. 4 is a cross'sectional view of the apparatus as shown in FIG. 3 andtaken along reference line IV-IV thereof;

FIG. 5 is a longitudinally sectioned view of an exemplary venturiconstruction arranged in accordance with my invention and useful in theembodiments of the exhaust systems depicted or described herein;

FIG. 5A is a partial view similar to FIG. 5 and showing a modifiedaperture entrance structure;

FIG. 6 is a partial longitudinally sectioned view of still another formof my conversion system wherein a pair of venturi structures are mountedin series within an exhaust duct or the like; and

FIG. 7 is a partial longitudinally sectioned view of still anotherventuri construction according to the invention and useful in theexhaust conversion systems described herein,

Referring now more particularly to the figures and initially I to FIG. 1of the drawings, the exemplary form of my exhaust conversion system oranti-pollution means shown therein is adapted for use with aconventional gasoline or diesel internal combustion engine or the like,having a conventional exhaust manifold 12 and tailpipe 14, whichnormally is secured directly to the outlet port 16 of the exhaustmanifold 12. The tailpipe l4 and manifold outlet 16 and associatedcomponents form an exhaust duct 15. In this arrangement, however, thetailpipe 14 which is provided with a conventional connecting flange 18is spaced from the exhaust manifold outlet port 16 which is alsoprovided with a conventional connecting flange 20. The exhaust manifold12 is provided with the usual number of inlet ports 22 whereby theexhaust manifold is joined to the engine block in alignment with theindividual cylinder exhaust ports. The direction of flow of exhaustfluids through the exhaust system thus far described is denoted by flowarrows 24. As mentioned previously, my exhaust conversion system can beemployed in exhaust ducts coupled to apparatus other than that shownherein, for example in various types of furnace and oven ducts and inconnection with other process equipment. It is contemplated further thatthe exhaust gases need not be partially combustible in the ordinarysense of the term. Rather, the exhaust gases can be partially reacted inthe general sense, and a reactant fluid can be inducted as describedbelow, which may be ambient air, oxygen, or some other fluid reactantcapable of converting the gases into nontoxic or innocuous effluents.

In the region of the flow arrows 24 the pulsating inlet exhaust streamsthrough the inlet ports 22, designated by dashed outline arrows 26, havebeen converted into a substantially steady flow of effluents. The usualcast iron structure of exhaust manifold 12 minimizes the temperaturedrop between the exhaust manifold inlet ports 22 and its outlet port 16.Accordingly, as noted previously, I have determined that the optimuminduction point for auxiliary combustion air is adjacent the manifoldoutlet port 16. A venturi inductor section 28 is inserted between themanifold outlet 16 and the tailpipe 14. In this arrangement of theinvention, the venturi section 28 is provided with an outside diametersimilar to the inside diameter of the outlet port 16 and tailpipe 14.Specifically, the outside diameter of the venturi section 28 is madeslightly larger than the aforementioned inner diameters with theexception of tapered portions 30 and 32 formed on the outer surface ofthe venturi section 28 at its leading and trailing edges 34, 36. Theseedges 34, 36 are substantially feathered or tapered to a relatively thinedge to minimize the fluid resistance of the venturi section 28. Thetapered surfaces 30, 32 can be cast integrally with the venturi section28 or alternatively, the tapered surfaces can be machined thereon withconventional equipment.

The tapered surfaces 30, 32 are preferably shaped so that portions ofthe venturi section 28 adjacent its leading and trailing edges 24, 26can be inserted initially and closely within the associated openings ofthe exhaust outlet port 16 and the tailpipe 14. When such insertion ismade, the venturi section 28 is securely mounted between the exhaustmanifold 12 and the tailpipe 14 by a number of tie-bolts 38 insertedthrough suitably aligned apertures in the exhaust manifold and tailpipeflanges l8 and respectively.

Communication between the exhaust manifold and the tailpipe 14 is thusestablished through throat 40 of the venturi section 28. It will beseen, then, that my conversion system as thus far described requireslittle or no additional space for the engine exhaust system, in theillustrated application. Moreover, my conversion system can be appliedto existing vehicles simply by separating the exhaust manifold 12 andthe tailpipe 14 a sufiicient distance to permit insertion of the venturisection 28. For this purpose, the existing exhaust forepipe can beappropriately shortened at the inlet mufiler clamp. Thus, my conversionsystem can also be applied to existing vehicles and need not benecessarily installed by the manufacturer.

In order to induct auxiliary combustion air into the vehicle exhaustsystem 12-14 in the area of the hottest portion of the nonpulsatingeffluent, the venturi section 28 is provided with a circumferentialarray of radial openings 42 which open into the venturi throat 40. Inthis arrangement, eight such openings are employed although it will beunderstood that the number can be varied depending upon the size andcharacter of the internal combustion engine. As evident from FIG. 1 ofthe drawings, the length of the apertures 42 in comparison to theirdiameter is such that the apertures 42 impart a jetting action to theinducted auxiliary combustion air passing therethrough. A useful jettingaction is obtained when the length to diameter ratio of the venturiapertures varies between about three to one and about five to one. Inthe illustrated case, the jetting and mixing action optimizes when thelength to diameter ratio is in the neighborhood of 4 to I. This jettingaction together with the substantially normal disposition of theapertures 42 relative to the direction of exhaust gas flow 24 causes theinducted air to be thoroughly and uniformly mixed with the exhaustgases. When thus mixed and when thus provided with the proper amount ofcombustion air as determined by the venturi section 28, a substantiallycomplete combustion of the engine exhaust gases results throughout awide range of engine operating conditions. I

The outward extremities of the induction openings 42 communicate with acircumferentially extending groove 44 formed in this example in theouter periphery of the venturi section 28. The groove 44 together with aclosely fitting sleeve 46 form an inlet manifold for the inductionapertures 42. The sleeve 46 can be applied to the outer surface of theventuri section 28 in a number of ways. For example, as shown in FIG. 1,the outer surfaces of the venturi section can be machined in the area ofits groove 44 and the sleeve 46 having its inner surface similarlymachined can be forced thereover as by tapping lightly with a hammer ormallet or other suitable tool. When thus positioned, the sleeve 46 canbe secured by spot welds 48. Alternatively, the sleeve 46 can beshrunk-fit upon the venturi section 28, in which case the spot welds 48will be omitted. In certain applications it may be desirable to seal thesleeve 46 to the adjacent outer surface of the venturi section 28 bysealwelding the lateral edges of the sleeve 46 to the adjacent outersurfaces of the venturi section 28. Obviously, the manifolding groove 44can be omitted from the venturi section 28 and provided instead on theadjacent inner surface of the sleeve 46.

Air is supplied to the manifolding groove 44 by means of a tappedaperture 50 or the like extending through the sleeve 46 to which asuitable fitting 52 and conduit 54 are secured. The conduit 54 desirablyis extended into the slip stream area of the vehicle to ensure theinduction of fresh auxiliary combustion air into the venturi section 28through the manifolding groove 44 and induction apertures 42. Suchinduction is effected by the reduced pressures in the venturi throat 40caused by the flow of exhaust effluents therethrough. Owing to theelevated temperatures of the exhaust effluents, secondary combustionthereof is immediately initiated adjacent the induction apertures 42.Because of the normally constant streamline flow of the exhaust effluentin the area of the exhaust manifold outlet 16 and downstream thereof arelatively stable flame front is established adjacent the inductionapertures 42. The stability of the flame front is further enhanced bythe symmetrical array of the apertures 42 and the transversedispositions thereof, all of which produce uniform and thorough mixingbetween the exhaust gases and the auxiliary combustion air. Mostimportantly, the flame front is particularly stabilized by thecontrolled turbulence and mixing of the inducted reactant and exhaustgases caused by the jetting action of the induction apertures. Thisjetting action coupled with location of the venturi member in thatportion of the exhaust duct where the effluent gases would haveexhibited a stream line flow, but for the presence of the venturi,further enhance the uniformity of the turbulence and attendant mixingaction. If desired, the induction conduit 54 can be disposed as denotedby the chain outline thereof in FIG. ll, so

that its inlet portion 56 is directed upstream of the vehicle slipstream, so that the slip stream aids the venturi effect in inducting airthrough the apertures 42 into the exhaust system, when the vehicle is inmotion.

During vehicle cruising and acceleration conditions, the suctionaleffects of the exhaust stream 24 flowing through the venturi section 28will regulate the amount of auxiliary combustion air required tocomplete the combustion of exhaust gases, in dependence upon the speedof the engine and the resultant quantity of exhaust gases producedthereby. Under conditions of relatively heavy engine acceleration,however, the proportion of combustible gases in the exhaust effluentincreases so that the quantity of auxiliary combustion air provided bythe induction effects of the. flowing exhaust gases will be insufficientfor complete combustion, if the combined flow area of the venturiapertures is undersized. On the other hand, during engine decelerationswhen the proportion of combustibles in the exhaust gases decreases, toomuch auxiliary combustion air may be inducted.

Accordingly, a modified form of my conversion system is shown in FIG. 2of the drawings for providing additional control of auxiliary combustionto meet these situations. In the latter arrangement of my invention, theventuri section 28 and sleeve 46 are coupled to an air induction conduit54 in which is mounted a throttle valve 58. The valve 58 can be providedin a variety of forms, a desirable form of which is a butterfly valvehaving vane 60 and operating lever 62. A stop 64 desirably is providedwithin the casing for engagement by the lever 62 to prevent fullyclosing the valve. The vane 60 desirably is biased toward its partiallyclosed position, as shown in FIG. 2 by means of spring 66.

The lever 62 in this example is operated by a cable 68 or the like whichin turn is moved by fluid motor 70, comprising for example the piston 72and cylinder 73. The position of piston 72 is controlled by thedepression in the intake manifold of the engine to which the piston andcylinder is coupled by conduit 74. Accordingly, when the engine is at ornear idling conditions the maximum manifold depression draws the lever62 via cable 68 against stop 64 so that only a small amount of auxiliarycombustion air can be drawn into the venturiapertures 42. On the otherhand, decreasing manifold depression with increasing accelerationpermits the spring 66 to draw lever 62 in the opposite direction towardthe full open position of the valve 58. With this arrangement themaximum available air through the conduit 54 is varied in proportion tothe load upon the associated engine. Thus, the venturi section 28 andassociated components are designed to supply adequate auxiliarycombustion air under maximum or near maximum engine load conditions. Fordecreasing load conditions the valve 58 will be increasingly movedtoward its closed position by the fluid motor 70, and this movement willvary with both the speed and accelerating conditions of the engine asreflected by the intake manifold depression. Thus, the amount ofauxiliary combustion air inducted by the venturi section 28 will berelated both to the speed of the engine and to the engine accelerationand deceleration. It is to be understood, of course, that the valvelever 62 can be manually operated by suitable linkage extending to andmounted on the vehicle dash or it can be coupled to the throttle linkageof the engine carburetor (not shown) for simultaneous action therewithso that the carburetor throttle plate (not shown) and the valve member60 will be moved simultaneously toward their opened and closed position.

The arrangements of my invention as shown in FIGS. 1 and 2 aresatisfactory for almost all vehicle operating conditions. However, whenthe vehicle is stationary with the engine idling, the velocity ofexhaust gases through the venturi section is usually not sufficient toinduce the venturi effect. Accordingly, the exhaust gases may passoutwardly through the venturi apertures 42 rather than drawing auxiliarycombustion air into the throat 40 of the venturi section 28 or 28. It isdesirable therefore to elongate the induction conduit 54 such that itsouter or intake end is positioned as far as practical from the cab orpassenger compartment of the vehicle.

However, elongation of the induction conduit54 or 54can be avoided withthe arrangement of my conversion system as shown in FIGS. 3 and 4 of thedrawings. In the latter arrangement the induction conduit 54" need beprovided only with suflicient length to reach the nearest slip streamarea of the vehicle. To prevent the outflow of exhaust gasestherethrough, a check valve 76 of simple and rugged construction ispositioned in the conduit 54" and is directed so that the induction ofauxiliary combustion air opens the check valve.

In this arrangement, the check valve 76 includes a generally circularvalve casing 78 mounted desirably in a vertical section 80 of theinduction conduit 54". An annular valve seat member 82 is mounted in thebottom of the casing 78 as viewed in FIG. 3 for cooperation with aconical seating surface 84 machined on the lower end portion of plunger86. The remainder of plunger 86, as better shown in FIG. 4 is of regularpolygonal configuration, for example square, to provide longitudinalpassages 88 between the flat sides of the plunger 86 and the encirclingwall of the valve casing 78. Altematively, the valve casing 78 can be ofa regular polygonal configuration while the preponderant portion ofplunger 86 can be of cylinder configuration, for example, to provide theaforementioned air passages. The related interior dimensions of thecasing 78 in any event are made slightly larger than the diametric ordiagonal dimension of the plunger to provide a guide therefor withoutbinding.

Upward movement of the plunger 86 is limited by the annular top wall 90of the casing 78. Desirably, the plunger 86 is fabricated from alightweight material so as not to interfere unduly with the inductedauxiliary combustion air through the conduit 54". On the other hand, thevertical mounting of the check valve 76 assures closing of the checkvalve during engine idle, inasmuch as both the weight of the plunger 86and the pressure of any outflow of exhaust gases through the apertures42 operate to close the check valve 76. A throttling valve such as thevalve 58' and associated components, as indicated by the chain outlinethereof in FIG. 3, can optionally be provided in the induction conduit54", depending upon the specific application of the invention.

With reference now to FIG. 5 of the drawings, I have discovered that animproved operation of the venturi structure such as that shown in FIGS.l-3 of the drawings results from the use of particular surfaceconfigurations and/or of dimensions and relationships falling withincertain critical ranges. Thus, I have found, for improved combustion airinduction and maximum exhaust gas combustion (resulting apparently andadditionally from an improved mixture of the reactants) over the widestvariation in engine speeds that the entrance or leading angle of theventuri member 28 should vary between 4565 with an angle of 60 beingoptimum within this range. Likewise, the angle of the trailing edges 102of the venturi structure 28 can vary between 3 6 and 7. The combustionair inlet apertures 42 desirably are located within the throat area 104,i.e., at the narrowest portion or throat area of the passage through theventuri. In the FIG. 5 arrangement, for improved results the throat area104 desirably is cylindrical, in contrast to the remaining inner venturisurfaces 105, 106 which are of convex curvatures. Desirably also theapertures 42 are disposed adjacent the median or mid-point of thecylindrical throat area 104 as denoted by chain reference line 108 inFIG. 5. Finally, I have determined that the operational characteristicsof the venturi 28' are further enhanced when the axial lengths of theconvex inner surface sections 105, 106 are in a ratio of about 114.5 to1:6.

In the venturi structure 28" of FIG. 5A, additional means are providedfor more thoroughly mixing the exhaust gases flowing through the venturi28" as denoted by arrow 110 with inducted combustion air flowing intothe venturi throat area 104' as denoted by flow arrow 112. In thisarrangement, some or all of the venturi apertures 42" are provided withinwardly extending hood means 114 comprising, in this example, arelatively short, truncated section of cylindrical conduit. I havefurther found that the mixing induced by the use of the hoods 114 isoptimized when the truncating angle relative to the cylindrical throatsurface 104, is between 25-35 and preferably about 30.

In FIG. 6 of the drawings exhaust duct including in this exampleforepipe 14, intermediate duct section 17, and manifold port 16 isprovided with a pair of series-mounted venturi sections 116, 118, eachof which has a manifold structure 44' and induction apertures 42'. Theventuri sections 116, 118 are spaced along the length of the exhaustduct 15 and in general are disposed at the same general location withreference to the exhaust manifold 12 (FIG. 1). With the exhaust gasesflowing through the duct 15' in the direction denoted by flow arrow 24,the apertures 42 of the first venturi section 116 are sized to induct aportion of the total require ment in combustion air. This results in apartial combustion and preheating of the exhaust gases and inconsequence the combustion is carried more nearly to completion adjacentthe second venturi section 118. Desirably, the venturi sections 116, 118are spaced such that maximum temperature of the combusting gases isachieved. In the example shown, the venturi sections 116, 118 desirablyare spaced a distance equivalent to about the length of one venturimember. Additional venturi members (not shown) can be so coupled inseries, depending upon a specific utilization of the invention.

A venturi member 120 having a modified configuration is illustrated inFIG. 7 for the purpose of still further enhancing the operationalcharacteristics of the exhaust conversion system 122. In the illustratedarrangement, the venturi member 120 is supported within exhaust ductdenoted generally at 124 after the manner of the preceding figures. Theventuri member 120 is provided with manifolding means 126 including inthis examplea circumferential ring or band 128 enclosing circumferentialgroove means, in this example a groove 130 formed on the outer peripheryof the venturi member 120. Obviously the groove can be formed on theband 128 instead. Communicating with the groove 130 are a plurality ofinduction apertures 132 which extend radially from the groove 13 tothroat area 134 of the venturi member 120.

The apertures 132 and throat area 134 desirably are located closer toleading edge 136 than to trailing edge 138 of the venturi member. Inthis arrangement, the throat area 134 of the venturi member isrepresented by a relatively blunt circumferential ridge or edge portion140 extending inwardly and circumferentially relative to the inner wallsurfaces of the venturi member 120. For improved induction and mixingcharacteristics the venturi apertures 132 preferably are disposedadjacent the venturi throat ridge 140 and desirably on the downstreamside thereof (flow arrow 142). Such characteristics are enhanced stillfurther by having the upstream edges of the inward openings of theventuri apertures 132 contingent or very nearly contingent to thedownstream side of the venturi throat ridge 140. In the illustratedarrangement, eight such venturi apertures 132 are employed, although itwill be apparent that a different number can be utilized depending uponthe specific employment of the invention. If desired, each of theventuri apertures 132 can be provided with the length to diameter ratiodiscussed previously for jetting characteristics and for a furtherimprovement in the mixing characteristics of the venturi member 120.

In the illustrated arrangement, the venturi throat ridge 140 desirablyis formed and defined by the inner venturi surfaces 144, 146. Theupstream venturi surface 144 defines an induction chamber 148 of theventuri member 128 while the downstream venturi surface 146 defines amixing chamber 150. In the arrangement of FIG. 7, the venturi surfaces144, 146 are disposed at a significant angle 152 to one another in theregion of their convergence to define the venturi throat ridge 140.Although illustrated as frusto-conical sections, the venturi surfaces144, 146 can be somewhat arcuate in either the convex or concave sensewhile still defining an appreciable throat angle 152.

For optimum results in the illustrated arrangement, the trailing edge138 of the venturi member 120 exhibits an angle 152 of between about 15to 25 with the venturi axis 154.

Similarly, the leading edge 136 of the venturi exhibits an angle 156 ofbetween about 20 and 30. The leading edge 136 can be truncated, asdenoted by reference numeral 158, in order to introduce a controllablyuniform turbulence into the exhaust gases flowing through the exhaustduct 124 (arrow 142). Such turbulence improves the induction and mixingcharacteristics of the venturi 120, which is, of course, furtherenhanced by the particular disposition of the venturi surfaces 144, 146.

I have found, in the illustrated arrangement, that optimum induction andadmixture are obtained when the diameter of the venturi throat 134 andthe outer diameter of the venturi member are in the ratio of about 2:3,respectively. Likewise, optimum results have been secured when thelengths of the induction chamber 148 and of the mixing chamber 150 arein the ratio of about 3:5, respectively. These optimum ratios will, ofcourse, vary depending upon a specific utilization and configuration ofthe venturi member 120. In the illustrated arrangement a considerableimprovement will still attain, although reasonable ratio ranges oneither side of the aforementioned optimum ratios respectively areemployed.

From the foregoing it will be apparent that novel and efficient exhaustconversion systems have been disclosed herein which can largelyeliminate the pollutants which would otherwise be exhausted to theatmosphere. With my arrangement the carbon monoxide and other harmful,combustible substances such as hydrocarbons are substantially fullyconverted into relatively harmless carbon dioxide and water vapor. Myconversion system is applicable to gasoline, diesel and other internalcombustion engines. For example, a venturi section such as venturisection 28 can be mounted in or adjacent the thrust nozzle of a jetengine. Such arrangement not only will ensure the complete combustion ofthe jet fuel but also will provide additional thrust. As notedpreviously, the venturi arrangements disclosed herein likewise can bemounted in the exhaust ducts of domestic and industrial furnaces, ovens,heaters, and the like where partially combusted exhaust gases are apt tobe encountered. My exhaust conversion system can be utilized withvarious types of reactional vessels and other process equipment for thepurpose of inducting additional reactant fluid into an exhaust duct orthe like associated therewith to ensure completion of the chemicalreaction.

In my exemplary utilization, I have found, upon application of myconversion system to the exhaust system of a dieselpowered truck thatthe usually dense, smoky exhaust which is characteristic of an operatingdiesel engine is almost entirely eliminated. Even under conditions ofmaximum load, only a relatively thin brown smoke is emitted from theexhaust instead of the usual dense black smoke. In this same connection,a smoky orange flame has been observed emanating 6 to 8 inches from thediesel exhaust outlet before installation of my conversion system. Afterinstallation only a barely visible dull red glow is apparent.

While I have shown and described certain presently preferred embodimentsof the invention and have illustrated presently preferred methods ofpracticing the same, it is to be distinctly understood that theinvention is not limited thereto but may be otherwise variously embodiedand practiced within the spirit and scope of the invention.

Iclaim:

1. A conversion system for an exhaust duct or the like through whichpartially reacted gases are circulated, said system comprising a venturiinduction member mounted in the exhaust duct and having acircumferential array of radially extending apertures for inducting areactant fluid into said duct upon passage of said gases there'through,said venturi member having inlet and outlet openings each havingsubstantially the same cross-sectional area as that of the adjacentinterior of said duct, said apertures being located in a thickenedportion of said venturi member and having a length-to-diameter ratiocapable of imposing a jetting action upon the reactant fluid passingtherethrough so that thorough mixing of said reactant fluid and saidgases is attained within said venturi member, said venturi memberincluding end portions partially and closely inserted into a pair ofduct sections respectively, and said venturi member being supportedbetween said sections.

2. The combination according to claim 1 wherein said exhaust duct iscoupled to an internal combustion engine, said venturi member beingcoupled between an outlet port of an engine exhaust manifold and anexhaust outlet pipe, said manifold and said pipe forming said exhaustduct sections.

3. A conversion system for an exhaust duct or the like through whichpartially reacted gases are circulated, said system comprising a venturiinduction member mounted in the exhaust duct and having acircumferential array of radially extending apertures for inducting areactant fluid into said duct upon passage of said gases therethrough,said venturi member having inlet and outlet openings each havingsubstantially the same cross-sectional area as that of the adjacentinterior of said duct, said apertures being located in a thickenedportion of said venturi member and having a length-to-diameter ratiocapable of imposing a jetting action upon the reactant fluid passingtherethrough so that thorough mixing of said reactant fluid and saidgases is attained within said venturi member, said venturi member beingprovided with a relatively shallow circumferentially extended groovecommunicating with said apertures, and a closely fitting sleeve havingan inlet port secured to the outer surface of said venturi member inclosing relationship with said groove, for delivering said reactantfluid to said apertures.

4. The combination according to claim 3 wherein a check valve is coupledto said inlet port and is directed to prevent an outflow of said gasestherethrough when the velocity of said gases through said duct isinsufficient to generate a venturi effect.

5. The combination according to claim 2 wherein conduit means includinga throttling valve are coupled to said venturi apertures, and means areprovided for moving said valve toward opened and closed positionsthereof in accordance with engine acceleration and decelerationrespectively, said moving means including fluid motive means coupled tosaid throttling valve and to an intake manifold of said engine forenergization thereby.

6. The combination according to claim 4 wherein said check valveincludes a casing and a plunger relatively closely fitted within saidcasing for guided movement therein, the cross-sectional configurationsof said plunger and of said casing being of differing regular geometricshapes to afford longitudinal flow passages between said plunger andsaid casing.

1. A conversion system for an exhaust duct or the like through whichpartially reacted gases are circulated, said system comprising a venturiinduction member mounted in the exhaust duct and having acircumferential array of radially extending apertures for inducting areactant fluid into said duct upon passage of said gases therethrough,said venturi member having inlet and outlet openings each havingsubstantially the same cross-sectional area as that of the adjacentinterior of said duct, said apertures being located in a thickenedportion of said venturi member and having a length-to-diameter ratiocapable of imposing a jetting action upon the reactant fluid passingtherethrough so that thorough mixing of said reactant fluid and saidgases is attained within said venturi member, said venturi memberincluding end portions partially and closely inserted into a pair ofduct sections respectively, and said venturi member being supportedbetween said sections.
 2. The combination according to claim 1 whereinsaid exhaust duct is coupled to an internal combustion engine, saidventuri member being coupled between an outlet port of an engine exhaustmanifold and an exhaust outlet pipe, said manifold and said pipe formingsaid exhaust duct sections.
 3. A conversion system for an exhaust ductor the like through which partially reacted gases are circulated, saidsystem comprising a venturi induction member mounted in the exhaust ductand having a circumferential array of radially extending apertures forinducting a reactant fluid into said duct upon passage of said gasestherethrough, said venturi member having inlet and outlet openings eachhaving substantially the same cross-sectional area as that of theadjacent interior of said duct, said apertures being located in athickened portion of said venturi member and having a length-to-diameterratio capable of imposing a jetting action upon the reactant fluidpassing therethrough so that thorough mixing of said reactant fluid andsaid gases is attained within said venturi member, said venturi memberbeing provided with a relatively shallow circumferentially extendedgroove communicating with said apertures, and a closely fitting sleevehaving an inlet port secured to the outer surface of said venturi memberin closing relationship with said groove, for delivering said reactantfluid to said apertures.
 4. The combination according to claim 3 whereina check valve is coupled to said inlet port and is directed to preventan outflow of said gases therethrough when the velocity of said gasesthrough said duct is insufficient to generate a venturi effect.
 5. Thecombination according to claim 2 wherein conduit means including athrottling valve are coupled to said venturi apertures, and means areprovided for moving said valve toward opened and closed positionsthereof in accordance with engine acceleration and decelerationrespectively, said moving means including fluid motive means coupled tosaid throttling valve and to an intake manifold of said engine forenergization thereby.
 6. The combination according to claim 4 whereinsaid check valve includes a casing and a plunger relatively closelyfitted within said casing for guided movement therein, thecross-sectional configurations of said plunger and of said casing beingof differing regular geometric shapes to afford longitudinal flowpassages between said plunger and said casing.